正方形______边相等．正方形周长=______．
正方形四条边相等．正方形周长=边长×4．
故答案为：四条、边长×4．
Why not buy him _________MP4 as__________ birthday present since he likes music?
A．an; the
B．the; the
C．an；a
D．a; a
葡萄球菌肺炎患儿使用抗生素的疗程是
A．体温正常后继续用药1周，总疗程3周B．体温正常后继续用药1周，总疗程4周C．体温正常后继续用药2周，总疗程4周D．体温正常后继续用药2周，总疗程5周E．体温正常后继续用药2周，总疗程6周
